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https://www.readbyqxmd.com/read/28937241/preejection-period-as-a-sympathetic-activity-index-a-role-of-confounding-factors
#1
J Krohova, B Czippelova, Z Turianikova, Z Lazarova, I Tonhajzerova, M Javorka
In previous studies, one of the systolic time intervals - preejection period (PEP) - was used as an index of sympathetic activity reflecting the cardiac contractility. However, PEP could be also influenced by several other cardiovascular variables including preload, afterload and diastolic blood pressure (DBP). The aim of this study was to assess the behavior of the PEP together with other potentially confounding cardiovascular system characteristics in healthy humans during mental and orthostatic stress (head-up tilt test - HUT)...
September 22, 2017: Physiological Research
https://www.readbyqxmd.com/read/28912359/left-ventricular-strain-rate-is-reduced-during-voluntary-apnea-in-healthy-humans
#2
Joshua R Smith, Shelbi L Sutterfield, Dryden R Baumfalk, Kaylin D Didier, Shane M Hammer, Jacob Troy Caldwell, Carl J Ade
During an apneic event, sympathetic nerve activity increases resulting in subsequent increases in left ventricular afterload and myocardial work. It is unknown how cardiac mechanics are acutely impacted by the increased myocardial work during an apneic event. 10 healthy individuals (23 ± 3 yrs) performed multiple voluntary end-expiratory apnea (VEEA) maneuvers exposed to room air, while a subset (n=7) completed multiple VEEA exposed to hyperoxic air (100% FiO2). Beat-by-beat blood pressure, heart rate and stroke volume were measured continuously...
September 14, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28900761/a-novel-multi-objective-physiological-control-system-for-rotary-left-ventricular-assist-devices
#3
Anastasios Petrou, Marcial Monn, Mirko Meboldt, Marianne Schmid Daners
Various control and monitoring algorithms have been proposed to improve the left-ventricular assist device (LVAD) therapy by reducing the still-occurring adverse events. We developed a novel multi-objective physiological control system that relies on the pump inlet pressure (PIP). Signal-processing algorithms have been implemented to extract the required features from the PIP. These features then serve for meeting various objectives: pump flow adaptation to the perfusion requirements, aortic valve opening for a predefined time, augmentation of the aortic pulse pressure, and monitoring of the LV pre- and afterload conditions as well as the cardiac rhythm...
September 12, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28900153/genetic-ablation-of-fgf23-or-klotho-does-not-modulate-experimental-heart-hypertrophy-induced-by-pressure-overload
#4
Svetlana Slavic, Kristopher Ford, Magalie Modert, Amarela Becirovic, Stephan Handschuh, Andreas Baierl, Nejla Katica, Ute Zeitz, Reinhold G Erben, Olena Andrukhova
Left ventricular hypertrophy (LVH) ultimately leads to heart failure in conditions of increased cardiac pre- or afterload. The bone-derived phosphaturic and sodium-conserving hormone fibroblast growth factor-23 (FGF23) and its co-receptor Klotho have been implicated in the development of uremic LVH. Using transverse aortic constriction (TAC) in gene-targeted mouse models, we examine the role of Fgf23 and Klotho in cardiac hypertrophy and dysfunction induced by pressure overload. TAC profoundly increases serum intact Fgf23 due to increased cardiac and bony Fgf23 transcription and downregulation of Fgf23 cleavage...
September 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28895507/functional-impact-of-exercise-pulmonary-hypertension-in-patients-with-borderline-resting-pulmonary-arterial-pressure
#5
Rudolf K F Oliveira, Mariana Faria-Urbina, Bradley A Maron, Mario Santos, Aaron B Waxman, David M Systrom
Borderline resting mean pulmonary arterial pressure (mPAP) is associated with adverse outcomes and affects the exercise pulmonary vascular response. However, the pathophysiological mechanisms underlying exertional intolerance in borderline mPAP remain incompletely characterized. In the current study, we sought to evaluate the prevalence and functional impact of exercise pulmonary hypertension (ePH) across a spectrum of resting mPAP's in consecutive patients with contemporary resting right heart catheterization (RHC) and invasive cardiopulmonary exercise testing...
July 2017: Pulmonary Circulation
https://www.readbyqxmd.com/read/28895094/fluid-loading-and-norepinephrine-infusion-mask-the-left-ventricular-preload-decrease-induced-by-pleural-effusion
#6
Kristian Borup Wemmelund, Viktor Kromann Ringgård, Simon Tilma Vistisen, Janus Adler Hyldebrandt, Erik Sloth, Peter Juhl-Olsen
BACKGROUND: Pleural effusion (PLE) may lead to low blood pressure and reduced cardiac output. Low blood pressure and reduced cardiac output are often treated with fluid loading and vasopressors. This study aimed to determine the impact of fluid loading and norepinephrine infusion on physiologic determinants of cardiac function obtained by ultrasonography during PLE. METHODS: In this randomised, blinded, controlled laboratory study, 30 piglets (21.9 ± 1.3 kg) had bilateral PLE (75 mL/kg) induced...
September 11, 2017: Intensive Care Medicine Experimental
https://www.readbyqxmd.com/read/28891509/role-of-the-medullary-lateral-tegmental-field-in-sympathetic-control
#7
Michael George Zaki Ghali
The sympathetic nervous system maintains and regulates arterial pressure and tissue perfusion, via control of cardiac output and vasomotor tone. Sympatho-vascular-mediated increases in blood pressure are effected by arterioloconstriction, which causes an increase in afterload, and/or venoconstriction, which increases venous return, left ventricular preload, and consequently, the force of cardiac contraction via Frank-Starling mechanisms; withdrawal of sympathetic drive elicits reciprocal effects. Spinalization reduces mammalian arterial pressure to 40-50 mm Hg consequent to the elimination of descending medullary pre-sympathetic bulbospinal drive to preganglionic sympathetic fibers in the intermediolateral cell column of the spinal cord...
2017: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/28887718/measurement-of-hemodynamic-changes-with-the-axial-flow-blood-pump-installed-in-descending-aorta
#8
Eiji Okamoto, Tetsuya Yano, Hidekazu Miura, Yasuyuki Shiraishi, Tomoyuki Yambe, Yoshinori Mitamura
We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43...
September 8, 2017: Journal of Artificial Organs: the Official Journal of the Japanese Society for Artificial Organs
https://www.readbyqxmd.com/read/28882231/hemodynamic-response-to-nitroprusside-in-patients-with-low-gradient-severe-aortic-stenosis-and-preserved-ejection-fraction
#9
COMPARATIVE STUDY
James W Lloyd, Rick A Nishimura, Barry A Borlaug, Mackram F Eleid
BACKGROUND: Low-gradient severe aortic stenosis (LGSAS) with preserved ejection fraction (EF) is incompletely understood. The influence of arterial afterload and diastolic dysfunction on the hemodynamic presentation of LGSAS remains unknown. OBJECTIVES: The authors sought to determine the acute hemodynamic response to sodium nitroprusside in LGSAS with preserved EF. METHODS: Symptomatic patients with LGSAS and preserved EF underwent cardiac catheterization with comparison of hemodynamic measurements before and after nitroprusside...
September 12, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28857904/in-vivo-evaluation-of-physiologic-control-algorithms-for-left-ventricular-assist-devices-based-on-left-ventricular-volume-or-pressure
#10
Gregor Ochsner, Markus J Wilhelm, Raffael Amacher, Anastasios Petrou, Nikola Cesarovic, Silvan Staufert, Barbara Röhrnbauer, Francesco Maisano, Christofer Hierold, Mirko Meboldt, Marianne Schmid Daners
Turbodynamic left ventricular assist devices (LVADs) provide a continuous flow depending on the speed at which the pump is set, and do not adapt to the changing requirements of the patient. The limited adaptation of the pump flow (PF) to the amount of venous return can lead to ventricular suction or overload. Physiologic control may compensate such situations by an automatic adaptation of the PF to the volume status of the left ventricle. We evaluated two physiologic control algorithms in an acute study with eight healthy pigs...
September 2017: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/28857176/do-right-ventricular-trabeculae-gain-energetic-advantage-from-having-a-greater-velocity-of-shortening
#11
Toan Pham, June-Chiew Han, Andrew Taberner, Denis Loiselle
Our study aimed to ascertain whether the interventricular difference of shortening velocity, reported for isolated cardiac tissues in vitro, affects interventricular mechano-energetic performance when tested under physiological conditions using a shortening protocol designed to mimic those in vivo. We isolated trabeculae from both ventricles of the rat, mounted them in a calorimeter, and performed experiments at 37°C and 5 Hz stimulus frequency to emulate conditions of the rat heart in vivo. Each trabecula was subjected to two experimental protocols: (i) isotonic work-loop contractions at a variety of afterloads, and (ii) isometric contractions at a variety of preloads...
August 30, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28845582/pathophysiology-of-exercise-intolerance-in-pulmonary-arterial-hypertension
#12
REVIEW
Derek L Tran, Edmund M T Lau, David S Celermajer, Glen M Davis, Rachael Cordina
Pulmonary arterial hypertension (PAH) is a chronic disease with poor prognosis and important exercise limitation despite the proliferation of treatment options in the last decade. Chronically increased right ventricular (RV) afterload results in right heart failure and without treatment, rapid clinical deterioration is common. Exercise intolerance is the cardinal feature of the disease impacting upon quality of life and clinical outcome. The pathophysiological mechanisms that lead to reduced exercise capacity in this population are complex with ventriculoarterial uncoupling likely to be the predominant feature...
August 27, 2017: Respirology: Official Journal of the Asian Pacific Society of Respirology
https://www.readbyqxmd.com/read/28845316/acute-heart-failure-exacerbation-with-cardiogenic-shock-and-elevated-systemic-vascular-resistance-treated-with-a-combination-of-nicardipine-and-dobutamine-therapy
#13
Lydia E Issac, Setri Fugar, Naser Yamani, Burhan Mohamedali
Acute heart failure is a common reason for hospital admission and is usually caused by decreased cardiac output either as a result of an intrinsic cardiac issue or as a result of severe hypertension with elevated afterload. We present a patient with a history of HFrEF who presented with acute heart failure, found to have hypotension requiring Dobutamine support and an elevated systemic vascular resistance requiring Nicardipine drip, with subsequent recovery of cardiac function.
2017: Case Reports in Cardiology
https://www.readbyqxmd.com/read/28843372/multisource-rotating-shield-brachytherapy-apparatus-for-prostate-cancer
#14
Hossein Dadkhah, Karolyn M Hopfensperger, Yusung Kim, Xiaodong Wu, Ryan T Flynn
PURPOSE: Our purpose is to present a novel multisource rotating shield brachytherapy (RSBT) apparatus for the simultaneous precise angular and linear positioning of partially shielded (153)Gd brachytherapy sources in interstitial needles for the treatment of locally advanced prostate cancer. It is designed to lower the dose to nearby healthy tissues, the urethra in particular, relative to conventional high-dose-rate brachytherapy techniques. METHODS AND MATERIALS: Following needle implantation through the patient template, an angular drive mechanism is docked to the patient template...
June 20, 2017: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/28842527/mechanisms-contributing-to-cardiac-remodelling
#15
REVIEW
Qing-Qing Wu, Yang Xiao, Yuan Yuan, Zhen-Guo Ma, Hai-Han Liao, Chen Liu, Jin-Xiu Zhu, Zheng Yang, Wei Deng, Qi-Zhu Tang
Cardiac remodelling is classified as physiological (in response to growth, exercise and pregnancy) or pathological (in response to inflammation, ischaemia, ischaemia/reperfusion (I/R) injury, biomechanical stress, excess neurohormonal activation and excess afterload). Physiological remodelling of the heart is characterized by a fine-tuned and orchestrated process of beneficial adaptations. Pathological cardiac remodelling is the process of structural and functional changes in the left ventricle (LV) in response to internal or external cardiovascular damage or influence by pathogenic risk factors, and is a precursor of clinical heart failure (HF)...
September 15, 2017: Clinical Science (1979-)
https://www.readbyqxmd.com/read/28835976/-medicinal-treatment-of-tricuspid-valve-regurgitation
#16
REVIEW
M Lankeit, K Keller, C Tschöpe, B Pieske
The vast majority of tricuspid valve regurgitations are of low degree without prognostic relevance in healthy individuals; however, morbidity and mortality increase with the degree of regurgitation, which can be secondary to either primary (structural) or secondary (functional) alterations of the valve. Due to the frequent lack of symptoms, echocardiographic examinations should be annually performed in patients with higher degree (at least moderate) tricuspid valve regurgitation, in particular in the presence of risk factors...
August 23, 2017: Herz
https://www.readbyqxmd.com/read/28822668/intrinsic-wave-propagation-of-myocardial-stretch-a-new-tool-to-evaluate-myocardial-stiffness-a-pilot-study-in-patients-with-aortic-stenosis-and-mitral-regurgitation
#17
Cristina Pislaru, Mahmoud M Alashry, Jeremy J Thaden, Patricia A Pellikka, Maurice Enriquez-Sarano, Sorin V Pislaru
BACKGROUND: Left ventricular (LV) filling following atrial contraction generates LV myocardial stretch that propagates from base to apex with a speed proportional to myocardial elasticity. The aim of this study was to test the hypothesis that intrinsic velocity propagation of myocardial stretch (iVP) would be altered in patients with valvular disease and chronic LV pressure overload or volume overload, which may adversely affect mechanical properties of the LV tissue. A second aim was to compare iVP with flow propagation velocity in the chamber...
August 16, 2017: Journal of the American Society of Echocardiography
https://www.readbyqxmd.com/read/28819545/circulating-mirnas-in-pediatric-pulmonary-hypertension-show-promise-as-biomarkers-of-vascular-function
#18
Vitaly O Kheyfets, Carmen C Sucharov, Uyen Truong, Jamie Dunning, Kendall Hunter, Dunbar Ivy, Shelley Miyamoto, Robin Shandas
BACKGROUND/OBJECTIVES: The objective of this study was to evaluate the utility of circulating miRNAs as biomarkers of vascular function in pediatric pulmonary hypertension. METHOD: Fourteen pediatric pulmonary arterial hypertension patients underwent simultaneous right heart catheterization (RHC) and blood biochemical analysis. Univariate and stepwise multivariate linear regression was used to identify and correlate measures of reactive and resistive afterload with circulating miRNA levels...
2017: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/28818234/the-dutch-lymphedema-guidelines-based-on-the-international-classification-of-functioning-disability-and-health-and-the-chronic-care-model
#19
Robert J Damstra, Anne-Berth Halk
Lymphedema is a chronic and progressive condition due to an imbalance between lymphatic filtration and transport capacity. A relative overload of fluid is caused by lymphatic impairment (afterload impairment); an absolute overload is caused by increased filtration (preload raised). Lymphedema can result in considerable disability and loss of quality of life. The Dutch Society of Dermatology organized a task force to create guidelines using the International Classification of Functioning, Disability, and Health...
September 2017: Journal of Vascular Surgery. Venous and Lymphatic Disorders
https://www.readbyqxmd.com/read/28816352/pulmonary-artery-wave-propagation-and-reservoir-function-in-conscious-man-impact-of-pulmonary-vascular-disease-respiration-and-dynamic-stress-tests
#20
Junjing Su, Charlotte Manisty, Ulf Simonsen, Luke S Howard, Kim H Parker, Alun D Hughes
Detailed hemodynamic analysis may provide novel insights into the pulmonary circulation. Therefore, wave intensity and reservoir-excess pressure analyses were applied in the pulmonary artery to characterise changes in wave propagation and reservoir function during spontaneous respiration and dynamic stress tests. Right heart catheterisation was performed using a pressure and Doppler flow sensor tipped guidewire to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery in control subjects and patients with pulmonary arterial hypertension (PAH) at rest...
August 17, 2017: Journal of Physiology
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